NAC062 regulates apical growth and cytokinin signaling in the shoot stem cell niche of Arabidopsis thaliana

Stem cell fate in plants and animals is controlled by their niches. The mechanisms that determine the organization and maintenance of niches within the developing shoot apical meristem (SAM) are not well understood. Here, we report the role of NAC062, a membrane-localized transcription factor, in preserving niche functionality by regulating cytokinin (CK) signaling. Genetic and molecular evidence suggest that NAC062 affects the expression of AHK4, a receptor gene crucial to CK signaling in niche cells. NAC062 undergoes cleavage in response to cold stress in the SAM, thereby integrating environmental signals to control stem cell niche activity. Explants that express a constantly active form of NAC062 show greater shoot regeneration, which suggests that CK signaling is heightened within the regenerating tissue. Our analyses of NAC062 target genes highlight its role in shoot system development, senescence, and responses to abiotic stress. We provide a framework for understanding the maintenance of CK signaling homeostasis within the Arabidopsis SAM stem cell niche under normal and stress conditions.